Mechanical warewashing machines including dishwashers have been common in the institutional and household environments for many years. Such automatic warewashing machines clean dishes using two or more cycles which can include initially a wash cycle followed by a rinse cycle. Such automatic warewashing machines can also utilize other cycles, for example, a soak cycle, a pre-wash cycle, a scrape cycle, additional wash cycles, additional rinse cycles, a sanitizing cycle, and/or a drying cycle. Any of these cycles can be repeated, if desired and additional cycles can be used. Detergents and/or sanitizers are conventionally used in these warewashing applications to provide cleaning, disinfecting and/or sanitizing. In addition to detergents and sanitizers, rinse aids are also conventionally used in warewashing applications to promote drying and to prevent the formation of spots on the ware being washed. In order to reduce the formation of spotting, rinse aids have commonly been added to water to form an aqueous rinse that is sprayed on the ware after cleaning is complete.
A number of rinse aid products are currently known, each having certain advantages and disadvantages. A component of rinse aid formulations is a preservative or preservative system. A conventional preservative is isothiazolinone, including isothiazolinone blends, such as Kathon CG-ICP which is a 3:1 blend of 5-Chlor-2-methyl-4-isothiazolin-3-one and 2-Methyl-4-isothiazolin-3-one (CMIT/MIT). The preservative is included in the formulation to prevent growth of microorganisms in the intermediate dispenser sump solution of the rinse aid composition, which is created by spraying water onto a solid product to dissolve the solid (e.g. block) and generate about a use solution. Customarily, a 2-5% sump solution in water is generated and in order to achieve adequate preservation efficacy a use solution will require between 5-15 ppm active of the isothiazolinone blend in the sump. To achieve this use solution concentration the solid rinse aid product requires upwards of 220 ppm of the isothiazolinone preservative in the solid block, which may invoke the need for personal protective equipment (e.g. gloves) to handle the concentrated solid rinse aid composition. To prevent the need for safety protocols and eliminate any concerns of sensitivity upon skin contact with the concentrated solid rinse aid composition, there remains an ongoing need for alternative rinse aid compositions including the preservative systems.
Accordingly, it is an objective of the claimed invention to develop solid rinse aid compositions and methods of using the same for warewashing applications to provide desired cleaning and rinsing performance in safe and sustainable concentrated formulation.
A further object of the invention is to provide rinse aid compositions that do not require personal protective equipment to handle a concentrated solid composition.
Other objects, advantages and features of the present invention will become apparent from the following specification taken in conjunction with the accompanying drawings.